https://www.brightonandhovealbion.com/news/3968819
On sale dates:
STHs/1901 Club Members with 317+ points: Tue 16 Apr, 9am
STHs/1901 Club Members with 256+ points: Wed 17 Apr, 9am
STHs/1901 Club Members with 223+ points: Thu 18 Apr, 9am
All STHs/1901 Club Members: Fri 19 Apr, 9am
MyAlbion+...
Looks like they are doing the traditional method of Tiers, with Albion+ 7 days after on sale date.
For Burnley the windows meant that it went to Purchase History after 72 hours.